The present invention is directed to a fluid applicator tip that is positioned in contact with the surface of an object to which a fluid is being applied. More particularly, the applicator tip is used with a fluid applicator to apply a layer of fluid to the surface of the object during relative movement between the object and the fluid applicator.
One of the primary applications of the applicator tip is the automotive glass industry where the fluid applicator is used to apply various fluids to the edge of the windshield, lights, and back window. The applicator tip will be generally described with regard to this particular automotive application. However, it should be understood that this invention is also suitable for a wide range of other fluid applications. The automotive glass application is only one use and is not meant to limit the scope of the applications for the invention.
The invention is particularly adapted for the production of glazing units or window assemblies for automotive vehicles, although it will find utility generally in a great many other fields. Installation of fixed window units in earlier automotive vehicles generally involved manual installation of the glazing unit using suitable mechanical fasteners such as metal clips for securing the unit in the vehicle body, applying sealant around the marginal edges of the glazing unit, and positioning decorative trim strips around the unit to cover the junction between the marginal edges of the glazing unit and the adjacent portions of the vehicle body. Assembly and installation of such units was relatively slow and costly inasmuch as a considerable amount of labor was required. The procedure was not readily adaptable to being speeded up to accommodate increased automobile production line rates, nor was it adapted to being automated.
Efforts to overcome these disadvantages resulted in numerous improved window structures. Thus, unitary window assemblies were developed wherein a sheet of glass was provided with an adjacent peripheral frame, with a casting or gasket of molded material extending between the frame and the peripheral margin of the window to hold the glass sheet within the frame. Fasteners provided at spaced locations along the frame permitted the entire assembly to be guided into position over an appropriate opening in a vehicle and secured to the vehicle as a unit. Such unitary window units reduce the time required and simplify installation in the vehicle opening. However, due to the labor required in manually assembling the frame and gasket on the sheet of glass, the structures are relatively costly.
More recently, in order to eliminate the manual assembly, so-called encapsulated grazing units have been developed wherein individual sheets of glass or laminated glass units are formed with integral frame or gasket members molded and cured in situ by a reaction injection molding (RIM) process. One such process and resulting product is shown and described in U.S. Pat. No. 4,561,625 to Weaver. Such encapsulating glazing units can be fabricated with a minimum of hand labor, and the resulting units can be readily attached to the portions of the vehicle body defining the window openings during assembly of the vehicle.
As described in the aforementioned patent, such encapsulated units are fabricated by disposing a predetermined portion of the marginal periphery of a sheet of transparent material within a mold structure. A polymeric gasket forming material is injected into the mold cavity and cured in situ on the sheet to encapsulate the marginal peripheral edge portion of the sheet. The resulting assembly can then be readily attached to the body portion defining the periphery of a window opening during manufacture and assembly of a vehicle.
Due to the nature of the glass surfaces, it is known that the gasket materials may not form a permanent, long term bond directly to the glass. Thus, they may not maintain adhesion to the glass surface for a length of time consistent with the life of the automobile. Exposure to weather, moisture and sunlight, as well as other factors, may cause the gasket material to loosen from the glass with the passage of time, and ultimately to separate entirely from the glass. In order to improve the adherence of the gasket material to the glass and increase the service life of the encapsulated units to an acceptable level, it has been common practice to apply a coating of a liquid primer material to the affected surface of the glass prior to formation of the gasket thereon. Heretofore, this has been accomplished by manually painting a band of the primer material along the appropriate edge portion of the glass panel. Such a procedure may, for example, utilize a brush periodically dipped in a container of the primer material. The procedures are not satisfactory in that they are time-consuming, labor-intensive and may not result in a satisfactory coating of the primer material. Thus the primer layer, which is generally a urethane material, should be applied as a uniform, continuous, relatively thin band in order to function properly. Should the layer be of excessive thickness, it may separate within the layer along a cleavage plane, resulting in failure of the bond. Of course, if the layer is not of sufficient thickness or if certain areas are not coated, the primer layer would likewise be ineffective for its intended purpose. The primer, and particularly the solvent therefore, may be toxic in nature so that manual application thereof, particularly when using an open container of the primer, may require use of protective equipment by the workers. Such manual application processes also generally result in waste of the primer material and generally messy conditions in the work place. Due to the difficulty in controlling the width of manually applied bands, it may also be necessary to mask the work piece prior to application of the primer material.
Accordingly, there is a need in the industry for a fluid applicator tip that can effectively apply a coating of fluid to an object to overcome the deficiencies of the prior art.
Other objects and advantages of the present invention will become apparent to those skilled in the art upon a review of the following detailed description of the preferred embodiments and the accompanying drawings.
An applicator tip for applying fluid to the surface of an object is disclosed. The applicator tip has a base formed of plastic material having a first surface and a second surface. At least one aperture is extending through the base. A fluid supply port is operatively connected to the second surface of the base, the supply port is in communication with the at least one aperture in the base. A fluid application material is positioned on the first surface of the base. The fluid application material is positioned to receive fluid that passes through the aperture from the fluid supply port. The fluid application material is positioned to apply the fluid to the desired areas on an object. The fluid application material is secured to the first surface of the base by a portion of the base that is caused to be molten and fuses to the fluid application material.
The applicator tips set forth in this patent application are particularly suitable for use in automated or robotic applications that apply a coating material in a manner that has a very fast linear velocity. In such applications, the applicator tips must be designed to have a limited fluid reservoir or fluid holding capacity so that the tips have a quick response when the application of fluid is reduced, such as is necessary when traveling around a corner on an object that is being coated. The reduced fluid holding capacity is achieved by minimizing the thickness in volume of the fluid application material.
Prior applicator tips have been made with a large volume of felt, foam or other composite wicking material as a fluid application material to provide a very resilient pad for liquid deposition onto the object that is to be coated. The large pillow-like surface is required because the applicator tip is pressed manually against the surface of the object and is manually made to traverse the area of the object that is to be coated. The force and speed at which the prior applicator tips are used varies considerably from worker to worker and require a large holding capacity in the fluid application material. The consistent high speed and light touch of automated application systems, such large holding capacity for the fluid application material is neither necessary nor desirable.